MICROBIOLOGY OF THE INDIGENOUS MILK PRODUCTS

COURSE TITLE: MICROBIOLOGY OF MILK PRODUCT
                        COURSE NO. - DTM-222: CREDIT HRS - 2 (1+1)

       MICROBIOLOGY OF THE INDIGENOUS MILK PRODUCTS
                          Desiccated Milk Based Products
RAKESH KUMAR
ASSOCIATE PROFESSOR (DAIRY MICROBIOLOGY)
FACULTY OF DAIRY TECHNOLOGY
S.G.I.D.T., BVC CAMPUS,
P.O.- BVC, DIST.-PATNA-800014

INDIGENOUS MILK PRODUCTS
 The    term ‘indigenous milk products’ refers exclusively to dairy products of a
    particular region or country

   47% of total milk products in India is converted to various indigenous
    products

 These   products are the backbone of the Indian confectionary

In India, about 50% of the total milk produced is converted into various traditional milk
products. These products account for 95% of all the milk products consumed and it is worth
noting that the organized dairy industry handles only about 17 - 18% of the total milk
produced in the country. Rest of the milk is used by small scale sweet meat shops (Halwaies)
in unorganized manner.

Traditional Indian dairy products can be classified into six categories based on the principle
of manufacture
  Heat desiccated products
  Heat and acid coagulated products
  Fermented products
  Products made with addition of cereals
  Clarified butter fat (ghee)
  Frozen products

Indian dairy industry
            June 19, 2019

                            https://www.businesstoday.in

Chhanna are curds or cheese curds, originating
from the Indian subcontinent, made from buffalo or
regular cow milk by adding food acids such as
lemon juice instead of rennet and straining. It is
very similar or analogous to cottage cheese.

Paneer is a fresh cheese common in the Indian
subcontinent. It is an unaged, non-melting soft
cheese made by curdling milk with a fruit- or
vegetable-derived acid, such as lemon juice. Its
acid-set form, before pressing, is called chhana.

Kalakand is an Indian sweet made out of
solidified, sweetened milk and paneer. It is also
popular in Pakistan

Rasogulla is an Indian syrupy dessert popular in the Indian
subcontinent and regions with South Asian diaspora. It is
made from ball-shaped dumplings of chhanna and semolina
dough, cooked in light syrup made of sugar. This is done
until the syrup permeates the dumplings.

Shrikhand is an Indian sweet dish made of strained dahi.

Rabri is a sweet, condensed-milk-based dish, originating
from the Indian subcontinent, made by boiling milk on low
heat for a long time until it becomes dense and changes its
colour to off-white or pale yellow. Jaggery, spices, and nuts
are added to it to give it flavor. It is chilled and served as
dessert.

Peda or Pera is a sweet dish hailing from the Indian
subcontinent. Usually prepared in thick, semi-soft pieces, its
main ingredients are khoa, sugar and traditional flavorings
including cardamom seeds, pistachio nuts and saffron.

Kheer is a type of pudding from the Indian subcontinent,
made by boiling milk and sugar with one of the following:
rice, broken wheat, tapioca, vermicelli, or sweet corn. It is
flavoured with cardamom, raisins, saffron, cashews,
pistachios, almonds or other dry fruits and nuts.

Rasmalai or rossomalai is a dessert originating from the
eastern regions of the Indian subcontinent. The name
rasmalai is the Hindi cognate of Bengali: rosh, meaning
"juice", and molai, meaning "cream". It has been described
as "a rich cheesecake without a crust

Dahi is a traditional yogurt or fermented milk product,
originating from the Indian subcontinent, usually prepared
from cow's milk, and sometimes buffalo milk, or goat milk. It
is popular throughout the Indian subcontinent.

Kulfi or Qulfi is a frozen dairy dessert originating in the
Indian subcontinent in the 16th century. It is often described
as "traditional Indian ice cream".

Lassi is a popular traditional dahi-based drink that originated
in the Indian subcontinent. Lassi is a blend of yoghurt, water,
spices and sometimes fruit. Sweet and mango lassis are just
like milkshakes. Bhang lassi is infused with the drug
cannabis in the form of bhang.

Gulab jamun is a milk-solid-based sweet from the Indian
subcontinent, popular in India, Nepal, Pakistan, the
Maldives, and Bangladesh, as well as Myanmar.

Barfi, borfi or burfi is a dense milk-based sweet from the
Indian subcontinent, and a type of mithai. The name is a
derivative of the Persian word barf, which means snow. A
few of the famous varieties of barfi include besan barfi,
kaaju barfi and pista barfi.

Sandesh is a dessert, originating from the Bengal region in
the eastern part of the Indian subcontinent, created with
milk and sugar. Some recipes of Sandesh call for the use
of chhanna or paneer instead of milk itself.

DESICCATED MILK –BASED PRODUCTS

   Dehydrated or concentrated milk products
   Gulabjamun
   Peda
   Rabri
   Kulfi

Variety of heat desiccated (khoa-based) sweets of Indian sub-continent

Gross composition (%) of some heat desiccated traditional milk products

                                Prasad Rasane*, Beenu Tanwar, and Anirban Dey
                                September - October 2015 RJPBCS 6(5) Page No. 39.

BIS* standards for three khoa varieties

                                 Source: Aneja et al. (2002)
                                 *BIS: Bureau of Indian Standards

GULABJAMUN
 Popular   khoa-based sweet

 Composition:

                Fat            10%
                Protein        6%
                Sugar          42%
                Acidity        0.6%

Production of Gulab Jamun from khoa

Factors affecting the microbiological quality of gulabjamun:
 Quality   of khoa
 Quality   of floor and water
 Quality   of sugar
 Quality   of nuts
 Contamination       from utensils and soil
 Packaging

Defects of gulabjamun:
   Stale and sour flavour

PEDA

 It   is the sandesh of north

Composition:
               Moisture          14%
               Fat               19%
               Protein           15%

Production of Peda from khoa

Production of Barfi from khoa

Typical microflora of market khoa based sweets

MICROBIOLOGICAL QUALITY OF PEDA

 Microbial number

 Microbial types

 Quality   of milk
 Production   hygiene
 Contamination from     utensils
 Soil   contamination
 Unclean   handlers

✓ Khoa serves as a favorable medium for the growth of a variety of contaminating
  microorganisms due to its high moisture content and high nutritive value.

✓ The market khoa can be kept in good condition for 48 h under normal conditions and
  thereafter deteriorates due to microbial action.

✓ These organisms gain access as contaminants from different sources in to product.

✓ The rapid spoilage of khoa is due to contamination with molds from different sources.

✓ A number of research work were carried out to know the microbiological status of khoa
  and khoa based sweets in different parts of the country.

DEFECTS
 Rancidity

 Sour   flavour
 Mold   growth
 Shelf-life:Samples with MAP (modified atmosphere packaging ) increase shelf-life
  of 15 days at 37˚C and at 20˚C increase to 30 days.

Mould growth --- Storage of Khoa at ambient and also at lower temperatures favours
the growth of molds which impart off-flavours and also produce certain mycotoxins
under favourable conditions. High no. of mold growth observed due to high moisture
content in the product, air leakage in the packed product, high humidity and aeration in
storage room etc.

Control measures
Since molds usually enter the product through aerial contamination, proper sanitation
through cleaning and fumigation of the dairy environment would control the problem.
Apart from this, mold contamination in the product can also be tackled through control of
humidity and aeration in the processing and packaging room.

•The moisture level in khoa should not be allowed to exceed the prescribed limits.

•Khoa should be stored in air-tight packages.

•Treatment of wrapping paper with antifungal agents like potassium sorbate controls mold
growth. However, use of such chemicals in the product is not permissible.

Types of micro flora in khoa and khoa based products
❑ Various groups of bacteria (acid producers, proteolytic, chromogenic, lipolytic, aerobic
  sporeformers, psychrotrophs, thermophiles, pathogens), yeasts and moulds have been
  reported to occur in khoa.

❑ Psychrotrophic bacteria mainly Pseudomonas, Achromobacter, Flavobacterium and
  Alcaligenes have been isolated from peda.

❑ On the basis of comparative analysis of khoa, burfi and peda, khoa contained higher
  population of yeasts and moulds than burfi or peda.

❑ The composite microflora of market burfi and peda was studied in which bacteria, yeasts
  and moulds were isolated from both the products, though the proportion of yeasts and
  moulds was extremely low as compared to bacteria. Among the bacteria, Gram-positive
  (mainly cocci) predominated in both the products.

Microbiology of khoa:
Khoa is a favourable medium for the growth of microbes on account of its nutritive value
and moisture content. The unsatisfactory practices generally followed in its production,
handling and storage in unorganized sector results in poor shelf life. Although during
manufacture of khoa, milk is subjected to drastic heat treatment, the aerobic spore formers
are known to survive such heat treatment and may outnumber other types of micro-
organisms, thereby suggesting that the survivors might multiply during subsequent storage.
The possibility of contaminants gaining entry into these products during subsequent
handling also cannot be ruled out.
A number of research studies showed the effect of antifungal agents on keeping quality of
khoa. They treated the samples with natamycin (0.5%) and potassium sorbate (0.3%). It
showed lower yeast and molds counts during storage at 30°C and also at 5°C.

Chavan & Kulkarni (2006) made efforts to improve the microbiological quality of khoa by
solar radiation and microwave heating. The application of microwave heating was observed
to be quite superior in reducing the total bacterial count, yeast and mold count (YMC) and
spore count. It also showed very slow rate of increase during storage for a week. Use of solar
radiation through convex lens showed promising results in reducing microbial counts and
particularly more effectively on YMC.
    A study was conducted to analyze bacterial contaminants / pathogens in khoa samples
sold in Madhya Pradesh in India. A total of 50 samples of khoa were brought from different
localities of Madhya Pradesh at random. Bacterial colony counts were also performed on
these samples. Staphylococcus and Streptococcus species were the predominant isolates. The
viable counts obtained ranged from 1.3x104 to 2.1x106 cfu/g. Contamination of khoa by
pathogenic bacteria could be an important factor of gastrointestinal infections including food
poisoning and food borne illness.

Heat processing of milk having 3.5 - 6.5% fat at either 63°C or 73°C eliminated all
Escherichia coli. Under similar processing conditions, Potassium sorbate (3000 ppm)
appeared more effective in inhibiting the growth of selected yeast and molds in khoa at
7°C compared to ascorbic acid (3000 ppm). Reducing the water activity (aw) of khoa
from 0.97 to 0.93 did not appear to enhance the preservative effect. The reduction of
E.coli or Staphylococcus aureus in khoa during prolonged storage at 6–7°C was less than
one log cycle, regardless of aw or preservative type. Survival of Staphylococcus aureus in
khoa appeared to be enhanced with a decrease in aw (Sohal et al. 1993). A study was
conducted to identify the incidence of different microorganisms in air and khoa samples
collected from different sections of a khoa plant. Penicillium citrinum was found to be
predominantly present in both air (24%) and khoa samples (27%). The other molds
encountered were Geotricum candidum, Mucor racemosus, Aspergillus niger,
Syncephalastrum oxysporum, Rhizopus stolonifer, Cladosporium cladosporioides, Absidia
corymbifera and Pacilomyces variotti (Rajarajan et al. 2007).

Pathogenic organisms from khoa, burfi and peda
    A number of pathogens like Salmonella typhi, Shigella dysenteriae, Vibrio cholerae
and E. coli are able to survive for long periods during storage of khoa. Subsequently, a
number of related studies have revealed the occurrence of staphylococci, especially those
of heat stable, coagulase positive, enterotoxin producing types in khoa, burfi and peda.
Drug resistant coliforms and enteropathogenic E. coli have also been isolated from khoa.
Although coliforms are heat labile, their isolation from large samples of the product
indicates post-processing contamination. The presence of coliforms may also indicate the
likely presence of potential pathogens like Salmonella, Shigella etc. in the product.
Contamination of khoa, peda and burfi with Salmonella schottmuelleri and Shigella
flexneri has also been found to correlate with faecal contamination. It was proved that S.
aureus a potent food poisoning organism, can multiply in khoa, peda and burfi at the
ambient storage temperature as well as at 37ºC.

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